Modular and stackable tray assembly

ABSTRACT

A system of open top trays of variable heights arranged to be stacked in any arrangement and with the trays in a stacked position defining a common interface datum plane between adjacent trays and releasably locked together. Each tray includes a bottom, longitudinal and transverse perimeter walls, with the perimeter walls being inclined outwardly and terminating in an upper rim, with the perimeter of each tray having the same dimensions regardless of its height. A latch handle is rotatably mounted on each transverse wall at a distance d 1  below the datum plane. A latch hook protrudes outwardly from each transverse wall at a distance d 2  above the datum plane with the latch handle having a locking tab for engaging an associated latch hook of an above positioned tray to releasably lock the trays together.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an assembly of individual trays ofdifferent heights which can be releasably locked together and carried asa single unit.

2. Description of the Prior Art

Boxes, and particularly compartmentalized boxes, for storing craft,fishing hardware and other small items (e.g., beads, lures, screw, etc.)are generally configured as single units with lids. Each unit isgenerally carried separately or stacked in an unsecured arrangement.Picking up and transporting a pile of such boxes can easily cause anunexpected separation of the piled boxes spilling the contents thereof.

Stackable storage containers which can be releasably locked together areknown as illustrated, for example, in U.S. Pat. No. 3,339,725 (“'725patent”); U.S. Pat. No. 4,619,363 (“'363 patent”); and U.S. Pat. No.6,273,258 (“'258 patent”).

The '725 patent employs a flat sheet (1) of cardboard or the like withthe central section extending over the top container and the endsections extending along the sides of the single or stacked container(s)and secured to the beaded rim(s) surrounding the openings(s) of thelower container(s). The sheet (1), which holds the containers together,constitutes an extra component and does not provide a particularlyreliable/reusable locking system.

The '363 patent discloses a storage unit in which two trays of differentheights and apparently vertically aligned side walls may be stacked andcarried as a unit. A separate connecting element (13) is releasablysecured between the sides of each pair of stacked trays. While theconnecting elements would apparently provide a secure lockingarrangement between the several trays, they would be cumbersome to use.The patent refers to the possible use of a hinged connecting element, asan alternative. However, no specifics are given as to its construction.

The '258 patent discloses a stackable container system for storingfoodstuffs in which identical containers are secured together byflexible flaps (18). Such a flexible flap arrangement is notparticularly robust. Also, absent the presence of the lid 22, there isno convenient handle with which to carry the stacked containers.

There is a need for a economical and stackable tray assembly with arobust locking mechanism, particularly for a stackable tray system inwhich the trays have different heights with optional dividers to formindividual compartments within the trays. For economic reasons trays andother containers for storing small items are often injection molded of aplastic material such as polypropylene, polyethylene or copolymers. Asplit two-part mold can be employed to form straight peripheral or sidewalls in such trays. While the use of a single non-split mold willresult in a simpler and less expensive molding process, the peripheralwalls must be outwardly inclined (i.e., draft angle) in order to removethe molded tray from the mold. The releasable locking arrangement of myinvention accommodates stacked trays of different heights and the use ofa single mold for each tray height.

SUMMARY OF THE INVENTION

A system for open top trays of variable heights arranged to be stackedtogether in any arrangement, in accordance with the present invention,comprises a group of trays with each tray having a bottom andlongitudinal and perimeter walls which terminate in an upper edge or rimdefining an opening through which articles may be placed in and removedfrom the tray. Preferably a plurality of dividers are mounted in thetray to form individual compartments. The peripheral walls have aninwardly stepped or undercut section joined to the bottom which undercutsection nests on the rim of the lower tray in a complementary manner tosubstantially align the peripheral walls of the nested trays with therim of each tray having the same dimensions regardless of the trayheight. The trays in a stacked position define a common interface datumplane coincident with the rim of the lower tray. A latch handle isrotatably mounted on the exterior of each transverse perimeter wallabout a rotational axis located at a distance d₁ below the datum planeand a latch hook protrudes outwardly from each transverse wall at adistance d₂ above the datum plane. The latch handle includes a lockingtab arranged to engage the latch hook of an above positioned tray (orlid) when the latch handle is rotated to a closed position.

Preferably each latch handle is rotatably mounted on an axle moldedintegrally with the transverse walls and spaced outwardly from arecessed central section thereof Alternatively the latch handles may beprovided stub axles positioned in an axle receiving openings in thetransverse walls adjacent a recessed central section thereof.

Preferably the rotational axis of the latch handles and the latch hooksare separated by distances d₃ and d₄, respectively, regardless of theheight of the tray. The underside of the latch handle (in the lockedposition) has a generally semicylindrical shape to provide a userfriendly handle portion for lifting and transporting stacked trays.Preferably the trays are provided with integrally molded or removabledividers to form compartments within the individual trays.

In addition the assembly includes a lid with a top wall, longitudinaland transverse side walls with a latch hook extending outwardly fromeach transverse wall and above the datum plane by the distance d₂ forengagement by the locking tab of an associated latch handle on theunderlying tray. The lid further includes a pivotal handle in the centersection of the lid top wall to accommodate the hand of a user desiringto lift and transport the stacked assembly.

The modular and stackable tray assembly of the present invention maybest be understood in reference to the following description taken inconjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a stackable tray assembly including acover or lid in the stacked and locked position in accordance with thepresent invention.

FIG. 2 is a side elevational view of the assembled trays of FIG. 1.

FIG. 3 is a front elevational view of the assembled trays of FIG. 1.

FIG. 4 is an exploded disassembled perspective view of the trays of FIG.1.

FIGS. 5 and 6 are perspective views of the lower and assembled lower andintermediate trays shown in FIG. 1, respectively.

FIG. 7 is a cross sectional view, partially broken away, taken alonglines 7-7, of FIG. 2, showing the releasable locking arrangement for theindividual trays with the dividers illustrated in FIG. 4 not shown forclarity.

FIG. 8 is an enlarged view of the releasable locking arrangement betweentwo of the trays of FIG. 7 illustrating various dimensions.

FIG. 9 is an enlarged view of the releasable locking arrangement betweenthe cover or lid and one of the trays of FIG. 7 illustrating variousdimensions.

FIGS. 10 and 11 are perspective views of the front and rear sides of thelatch handle, respectively.

FIGS. 12 and 13 are top and bottom plan views of the cover or lid,respectively.

FIG. 14 is a perspective view of the handle for the cover.

FIG. 15 is a perspective view of an alternative latch handle.

FIG. 16 is a partial perspective view of a transverse peripheral wall ofa tray showing an opening therein for receiving the stub axles of thealternative latch handle.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1-5 a tray system or assembly designatedgenerally at 10 of the present invention includes a plurality of opentop trays with a bottom tray 12, an intermediate tray 14, an uppermosttray 16 and a cover or lid 18.

The trays are injection molded, preferably with a one piece mold, of asuitable rigid thermoplastic material such as polypropylene,polyethylene or a copolymer. Preferably, the trays, i.e., at least two,have different heights, h. As an example, a set of four trays may haveheights of 4″, 3″, 2″ and 1¼″ and have suitable lengths and widths suchas 16″ and 8″, respectively. It is to be understood that the specificdimensions given are by way of example only.

As is illustrated more particularly in FIGS. 5 and 7, each tray includesa bottom wall 20, longitudinal peripheral walls 22, and transverseperipheral walls 24 (collectively “peripheral walls”) with theperipheral walls being inclined outwardly to the vertical (at an angledesignated as θ in FIG. 3) to accommodate removal from the mold. Theperipheral walls terminate in a an upper edge or rim 25 through whicharticles may be placed in and removed from the open trays. The angle θof the inclination may be in the range of 0.5° to 2° with the angledependent upon the height h of the tray so that the rim of the trayshave substantially the same dimensions for nesting purposes as will beexplained. The peripheral walls are joined to the bottom via an inwardlystepped or undercut section 23 (FIG. 7) which mates with the rim of thelower tray to align the peripheral walls and maintain the trays in anested arrangement. As is illustrated in FIG. 8 a horizontally orientedshelf 23 a of the undercut section rests on the rim 25 of the lowertray.

The longitudinal and transverse peripheral walls are joined at aradiused corner sections 26 (FIG. 5) with the center sections 22 a ofthe longitudinal walls recessed slightly, as illustrated, for decorativepurposes. A central section 24 a of the transverse walls is alsorecessed with axle 28 integrally molded into the side sections 24 b andspaced outwardly from the central section (FIG. 1) to accommodate anaxle receiving groove 30 a in a latch handle 30 (FIG. 14) rotatablymounted on the axle as will be explained in more detail (the sidesections 24 b extending perpendicularly outwardly from the centralsection 24 a). The center of the axle is supported via a stub supportmember 28 a which extends outwardly from the recessed center portion 24a. See FIG. 8. The peripheral walls include circumscribing outwardlyprotruding ribs 3 1, adjacent the rim, for decorative purposes. See FIG.5.

A protruding latch hook member 32 (extending upwardly from two spacedhorizontal ribs 32 a) is also integrally molded in the bottom of thecenter section 24 a of each transverse peripheral wall for receiving alocking tab 30 b on the latch handle when in its closed position to lockthe several trays together. See FIGS. 1, 8 and 9. The latch handle isformed with a tab 30 c which may be rotated by a user's finger to engageor disengage the locking tab from the latch hook 32 to lock or unlockthe trays. The underside 30 d of the bottom of the latch handle issemicircular in shape and serves as a handle for lifting one or a stackof trays. The center section of the bottom of the latch handle isnotched at 30 e to accommodate the stub support member 28 a. See FIGS.10 and 11.

As discussed earlier the trays, in a stacked position, with the undercutshelf 23 a of the upper shelf resting on the rim 25 of the lower shelf,define a datum plane coincident with the lower tray rim as isillustrated in FIG. 8.

The axle 28 is spaced below the datum plane by a distance d₁ with thelatch hook 32 spaced above the datum plane by a distance d₂ in each trayregardless of the tray height. The distance between the center of thelatch handle groove 30 a and the locking tab equals d₁+d₂. Preferablythe distances d₃ and d₄ between the axles 28 and latch hooks 32,respectively, on each tray, regardless of tray height, are the same sothat the axles and latch hooks will be aligned vertically (although indifferent planes as illustrated) with the trays in a stacked position asis illustrated in FIG. 7.

Referring now to FIGS. 1, 12 and 13 the cover or lid 18 includeslongitudinal and transverse perimeter walls 18 a and 18 b, respectively,with a center section 18c of each transverse wall being recessed foralignment with the recessed center sections 24 a of the trays in thestacked position. The sections 18 c are molded with protruding latchhooks 32′, aligned with the latch hooks 32, of the lower stacked trays.As is illustrated in FIG. 9 the locking tab 30 b of the lower tray latchhandle engages the latch hook 32′ to lock the cover to the underlyingtray(s). As is illustrated in FIG. 9, the distances d₅ and d₆ representthe distances between the axles 28 and latch hooks 30 b, respectively,from the recessed wall sections 28 a.

The lower end of the cover perimeter sections are formed with an overcutsection 18 d defining a horizontally extending shelf 18 e and anoverhanging vertically oriented skirt 18 f. The shelf 18 e rests on therim of the underlying tray and defines the datum plane for determiningthe distance d₂ as is best illustrated in FIG. 9. The skirt 18 f fitsover the outside of the rim and upper portion of the perimeter walls ofthe lower tray.

The upper side of the cover includes a depressed center section 18g,merged between side sections 18 h via vertically oriented stub walls 18i. The stub walls have openings 18 j for receiving stub axles 36 a of ahandle 36. See FIGS. 1 and 14. The longitudinal and peripheral sectionsof the cover include decorative curved sections 18 k merged with theovercut section 18 d.

As is best illustrated in FIG. 13 the underside of the center section ofthe cover is designated 18 g. Strengthening ribs 18 l are also includedon the underside of the cover.

Referring now to FIGS. 4 and 5 divider receiving guides 38 areintegrally molded to the interior surfaces of the longitudinal perimeterwalls of trays 12 and 14 with removable dividers 40 mounted in some ofthe guides. Each guide is formed by a pair of elongated opposedgenerally semicylindrical sections 38 a defining a narrow slottherebetween for receiving and releasably retaining a divider 40.Preferably the removable dividers are formed with semicylindrical endsections 40 a which are complementary with the elongated cavities formedby the sections 38 a. See FIG. 5.

One or more dividers 42 may be integrally molded with the trays asillustrated in tray 16 of FIG. 4. In addition vertically oriented spoolreceiving posts 42 may be integrally molded in a section of a tray.Alternatively, the posts 42 may be molded to a removable plate (notshown) for placement in a section of the tray as in FIG. 4.

The dividers may have a height, such as is illustrated in the tray 14,so that the bottom of a overlying tray will be positioned closely abovethe dividers to inhibit any articles from spilling from one compartmentto another in the event that the locked assembly is tipped upside down.

As an alternative to the latch handle and fixed axle arrangement shownin FIGS. 1 and 9-11, the latch handle (designated 40) may be in the formshown in FIG. 15 and 16 with stub axles extending into openings 42 inthe transverse wall side sections 24 b′. With either arrangement thelatch handle rotates about an axis of rotation located at distance d₁below the datum plane.

While the trays and cover may be molded of any suitable plastic, theyare preferably made of polypropylene. I have found that the nominal wallthickness t of 0.080″ for the trays is suitable while a somewhat greaterthickness may be preferable for the skirt sections of the top since thetop must carry the weight of the stacked assembly when the handle 36 isused to transport the underlying trays. It is to be noted that thesemicylindrical latch handle portions 30 d may be used to carry theassembled trays with or without the cover in place.

There has thus been described a novel modular and stackable trayassembly with the individual tray arranged to accommodate removable orstationary dividers to form compartments and a reliable locking systemto allow a stacked tray assembly to be conveniently carried with orwithout a cover. Various modifications to the invention will becomeapparent to those skilled in the art without involving any departurefrom the spirit and scope of the present invention as defined in theappended claims.

1. A system of open top trays of variable heights arranged to be stackedand releasably locked together in any arrangement independent of theindividual tray heights, the trays in a stacked position defining acommon interface datum plane between adjacent trays, each traycomprising: a bottom and longitudinal and transverse perimeter wallsterminating in an upper rim defining an opening through which articlesmay be placed in and removed from the tray, the perimeter walls beinginclined outwardly with respect to the vertical with the rim of eachtray having the same dimensions regardless of the height of the tray; anaxle spaced outwardly from each transverse wall to accommodate arotatable latch handle mounted thereon, the axle being located below thedatum plane by a first predetermined distance d₁; a latch hookprotruding outwardly from each transverse wall and located above thedatum line a second predetermined distance d₂; and a latch handlerotatably mounted on each axle, the latch handle having a locking tabarranged to engage the associated latch hook of an above positioned traywhen the latch handle is rotated to a closed position.
 2. The system ofclaim 1 wherein the peripheral walls include an inwardly stepped sectionjoined to the bottom with the stepped section providing a matinginterface with the upper edge of the peripheral walls of a belowpositioned tray and defining the datum plane so that when the trays arein a stacked relationship the peripheral walls of each container aresubstantially aligned.
 3. The system of claim 2 wherein the transversewalls have a recessed center section and wherein the axles and latchhooks are positioned in the center sections.
 4. The system of claim 2wherein each latch handle terminates at one end in the shape of aninverted j-hook defining a groove arranged to fit over the associatedaxle and terminates at the other end in a finger engaging surface withany intermediate inwardly extending locking tab, the j-hook portiondefining a convenient handle for carrying one or several stacked trays.5. The system of claim 4 wherein the longitudinal peripheral walls ofthe tray define a plurality of vertically oriented opposing dividerreceiving guides.
 6. The system of claim 5 wherein each guide is formedby a pair of elongated opposed generally semicylindrical sectionsdefining a narrow slot therebetween.
 7. The system of claim 2 whereinthe distance d₃ between the axles and the distance d₄ between the latchhooks are the same regardless of the height of the tray.
 8. The systemof claim 2 further including a cover having longitudinal and transverseperimeter sections with the transverse sections having a recessed centerportion with a protruding latch hook on each transverse center portionsection, the perimeter sections defining an overcut portion adjacent thebottom thereof with a horizontally oriented shelf arranged to engage therim of an underlying tray, the latch hook being positioned above theshelf by the distance d₂.
 9. The system of claim 8 wherein the perimetersections of the cover further define an overhanging vertically orientedskirt arranged to extend over the outside of the upper portion of theperimeter walls of an underlying tray.
 10. The system of claim 9 whereina rotatable handle is mounted on the top of the cover.
 11. An assemblyof compartmentalized trays of variable heights arranged to be stackedand releasably locked together, each tray comprising: a bottom andlongitudinal perimeter walls and transverse perimeter walls with theperimeter walls being inclined outwardly at angle θ and terminating inan upper rim defining an opening through which articles may be placed inand removed from the tray, each transverse wall having a centralsection; a plurality of dividers mounted in the tray to form individualcompartments; an axle positioned adjacent the upper edge and spaced fromthe central section of each transverse wall to accommodate a rotatablelatch handle mounted thereon; a latch hook protruding outwardly fromeach transverse wall adjacent the bottom in vertical alignment with theaxle; and a latch handle rotatably mounted on each axle, the latchhandle having a locking tab arranged to engage the associated latch hookof an above positioned tray when the handle is rotated to a latchedposition.
 12. The container assembly of claim 11 wherein θ is within therange of about 0.5° to 2°.
 13. The container assembly of claim 12wherein the peripheral walls include an inwardly stepped section joinedto the bottom with the stepped section accommodating the rim of anothercontainer so that when the containers are in a stacked relationship theperipheral walls of each container are substantially aligned.
 14. Thecontainer assembly of claim 13 wherein each latch handle defines agroove at one end which fits over the associated axle, a finger engagingsurface at the other end and an intermediate locking tab.
 15. Thecontainer assembly of claim 14 wherein each transverse perimeter wall isformed with an inwardly stepped center section with the axle extendingacross the center section adjacent the upper edge and an outwardlyextending latch hook disposed in the center section adjacent the bottom.16. A system of open top trays of variable height arranged to be stackedand releasably locked together in any arrangement independent of theindividual tray heights, the trays in a stacked position defining acommon interface datum plane between adjacent trays, each traycomprising: a bottom and longitudinal and transverse perimeter wallsterminating in an upper rim defining an opening through which articlesmay be placed in and removed from the tray, the perimeter walls beinginclined outwardly with respect to the vertical with the rim of eachtray having the same dimensions regardless of the height of the tray; alatch handle rotatably mounted on each transverse perimeter wall aboutan axis located below the datum plane by a first predetermined distanced₁; and a latch hook protruding outwardly from each transverse wall andlocated above the datum line a second predetermined distance d₂, thelatch handle having a locking tab arranged to engage an associated latchhook of an above positioned tray when the latch handle is rotated to aclosed position.
 17. The invention of claim 16 wherein the latch handleis formed with a central section and a stub axle extending outwardlyfrom the central section along the axis of rotation and wherein thetransverse perimeter walls define opposed openings for receiving thestub axles.
 18. The invention of claim 17 wherein the transverseperimeter walls include a recessed center section located betweenperpendicularly extending side walls, the side walls defining theopenings for the latch handle stub axles.
 19. The system of claim 18wherein the peripheral walls include an inwardly stepped section joinedto the bottom with the stepped section providing a mating interface withthe upper edge of the peripheral walls of a below positioned tray anddefining the datum plane so that when the trays are in a stackedrelationship the peripheral walls of each container are substantiallyaligned.
 20. The system of claim 19 wherein the longitudinal peripheralwalls of the tray define a plurality of vertically oriented opposingdivider receiving guides.
 21. The system of claim 20 further including acover having longitudinal and transverse perimeter sections with thetransverse sections having a recessed center portion with a protrudinglatch hook on each transverse center portion section, the perimetersections defining an overcut portion adjacent the bottom thereof with ahorizontally oriented shelf arranged to engage the rim of an underlyingtray, the latch hook being positioned above the shelf by the distanced₂.